The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.
Radio-frequency (RF) identification (RFID) is the wireless use of electromagnetic fields to transfer data, for the purposes of automatically identifying, detecting, positioning and tracking tags.
In some cases, RFID systems comprise RFID tags and readers. RF readers comprise an antenna and electronic power circuitry to locate nearby tags and receive encoded information using radio frequency communication. The reader emits high frequency radio waves that any nearby passive RF tag, which absorbs radio energy to power-up its own integrated circuit or load-modulate the radio energy to beam back an ID number to the reader. The reader can also write basic information to the chip on the tag. For example, if the RF tag is inside a book, a code written to the chip may indicate the book has been checked out. A security gate reader will then receive this information from the tag to allow the book to pass through.
Many models of reader are hand-held devices (resembling a barcode scanner or pricing gun), but they can also be fixed in place (such as in security gates or counter-tops) or even hidden completely (embedded in ceilings or walls).
A typical RFID tag consists of a microchip attached to a radio antenna mounted on a substrate. The microchip can store information such as vehicle license plate or payment related information. RFID tags, which use radio waves to communicate their identity and other information to nearby readers, can be passive or active. Passive RFID tags are powered by the reader and do not have a battery. Active RFID tags are powered by batteries and able to generate own radio signal.
RFID tags can store a range of information from one serial number to several pages of data. Readers can be mobile so that they can be carried by hand, or they can be mounted on a post or overhead. Reader systems can also be built into the architecture of a cabinet, room, or building.
These radio-frequency identification tags can be attached to objects such as vehicles, persons and other movable objects. The radio-frequency tags contain electronically stored information and may be accessed or programmed wirelessly by RFID readers in a distance.